A project to isolate, characterize and reverse the action of the primary gene product in the inherited disease, cystic fibrosis, has been successful in purifying a family of urinary and plasma proteins which inhibit mucociliary activity. Fractionation has been carried out by protein chemistry techniques including isoelectric focusing, affinity chromatography, gel filtration and ion exchange chromatography. Ultimately, the primary structure analysis will be completed on the cystic fibrosis mucociliary inhibitor (CFMI) and compared to any normal counterpart present in non-affected and homozygous normal individuals. Antibody preparation in hybridomas has been carried out using two purified urinary inhibitors. These will be utilized to test sera and urine of known cystic fibrosis homozygotes, obligate heterozygotes and amniotic fluid from mothers at high risk of having a child with cystic fibrosis. The antiserum will also be useful in detecting the normal counterpart of the cystic fibrosis mucociliary inhibitor and comparing its structure with that the CFMI. It will also be used to map the chromosomal location of the gene through somatic cell hybrids which have been constructed with cystic fibrosis fibroglasts and long term rodent cell lines.